From 62e0d47a8f0111b1ed8b7b32b8ac1d6403d57a63 Mon Sep 17 00:00:00 2001
From: pcherenkov <pcherenkov@gmail.com>
Date: Wed, 2 May 2012 16:28:41 +0400
Subject: [PATCH] bug988508: wal_mode, wal_fsync_delay documented

---
 doc/user/persistence-architecture.xml | 38 +++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/doc/user/persistence-architecture.xml b/doc/user/persistence-architecture.xml
index 5db4d1f3f0..d9f51dd494 100644
--- a/doc/user/persistence-architecture.xml
+++ b/doc/user/persistence-architecture.xml
@@ -69,6 +69,44 @@ provided SELECTs are run in their own connections, is unaffected
 by disk load.
 </para>
 
+<para>
+WAL writer ensures data consistency and synchronization
+between requesting fibers, WAL writer and disk by
+employing one the following modes of operation (designated by
+<emphasis>wal_mode</emphasis> and
+<emphasis>wal_fsync_delay</emphasis> configuration keys):
+<orderedlist>
+    <listitem><para><emphasis>write</emphasis>: fibers wait for their
+    data to be written to the log (no fsync(2));</para></listitem>
+    <listitem><para><emphasis>fsync</emphasis>: fibers wait for their
+    data, fsync(2) follows each write(2);</para></listitem>
+    <listitem><para><emphasis>fsync_delay</emphasis>: fibers wait for their
+    data, fsync every N=<emphasis>wal_fsync_delay</emphasis>
+    seconds (N=0.0 means no fsync(2) - equivalent to
+    <emphasis>wal_mode = "write"</emphasis>);</para></listitem>
+</orderedlist>
+</para>
+
+<!--
+<para>
+WAL writer ensures data consistency and synchronization
+between requesting fibers, WAL writer and disk by
+employing one the following modes of operation (designated by
+<emphasis>wal_mode</emphasis> and
+<emphasis>wal_fsync_delay</emphasis> configuration keys):
+<orderedlist>
+    <listitem><emphasis>write</emphasis>: fibers wait for their
+    data to be written to the log (no fsync(2));</listitem>
+    <listitem><emphasis>fsync</emphasis>: fibers wait for their
+    data, fsync(2) follows each write(2);</listitem>
+    <listitem><emphasis>fsync_delay</emphasis>: fibers wait for their
+    data, fsync every N=<emphasis>wal_fsync_delay</emphasis>
+    seconds (N=0.0 means no fsync(2) - equivalent to
+    <emphasis>wal_mode = "write"</emphasis>);</listitem>
+</orderedlist>
+</para>
+-->
+
 </section>
 <!--
 vim: tw=66 syntax=docbk
-- 
GitLab